Renal artery variants- Accessory renal artery

3D Volume rendered maximum intensity projection (MIP) CT angio images in a 29 year old male donor scheduled for donor nephrectomy showing Accessory renal artery on the left side with prehilar branching on right side.

Discussion:

• Multiple renal arteries are unilateral in approximately 30% of patients and bilateral in approximately 10%. 
• Accessory arteries usually arise from the aorta or iliac arteries anywhere from the level of T11 to the level of L4. 
• In rare cases, they can arise from the lower thoracic aorta or from lumbar or mesenteric arteries. 
• Usually, the accessory artery courses into the renal hilum to perfuse the upper or lower renal poles. 
• Prehilar arterial branching is another common variant that must be checked in patients being evaluated for donor nephrectomy.